Wireless Power 101: FOD Introduction

[MUSIC PLAYING] I hope you've had a chance to visit our wireless power overview at ti.com/wirelesspower. The overview covers many topics of interest to those of you just getting into wireless power and those of you looking to expand your knowledge.
Hi, I'm Dick Stacey, an Applications Engineer on TI's Battery Management Solutions team. In this session, I'm going to discuss the tools used for Foreign Object Detection, or FOD. Both the receiver and transmitter have to address the issue, but this will focus on the receiver FOD.
For this discussion, a foreign object is anything that will interfere with a magnetic field created by the transmitter that's not part of the solution. When placed inside the power transfer area, they can absorb the energy being transmitted and heat up, which can result in a poor user experience.
When a receiver is placed on the transmitter, the transmitter will begin to send power to the receiver, which in turn will negotiate for the power it needs for its system. During normal operation with no foreign object, the power transmitted equals the power received. When a foreign object is inserted into the system, it will absorb some of the energy sent from the transmitter.
The receiver will then need to request more power from the transmitter to compensate for the power loss to the foreign object. The wireless system may be able to determine if there is a foreign object present by comparing the received power reported to the transmitter with the actual transmitted power. If this delta becomes too large, there is something in the area absorbing the excess transferred power.
Once a preset threshold for maximum allowable power loss is reached, the transmitter is required to prevent the object from increasing past a given temperature threshold. In general, the transmitter will stop power transfer and set an error flag. Many of the TI transmitters would decrease the power being sent in an attempt to keep within an acceptable level in order to continue power delivery without creating excessive power losses.
Calibration is required by the receiver system to ensure it sends the correct power level to the transmitter. Calibration is required to account for any expected friendly metal losses. Examples of friendly metals include cameras, speakers, batteries, screws, and connectors. The receiver coil shielding is not only used to direct a magnetic field to the coil, but also to block as much magnetic field from impacting friendly metals as possible.
The next questions are do I have to calibrate each of the systems individually? And how do I calibrate my system for the friendly metals? The good news is once a system is calibrated, any duplicate systems can use the same calibration, as long as they're using exactly the same mechanical and electrical designs.
Now we'll discuss the tools available to do the calibration. Calibration of your system requires external tools, typically we use the AVID Technologies' Qi FOD transmitter to calibrate our receiver EVMs. The AVID tool requires a 19 volt power supply and a USB serial interface, which are both included with the system.
TI provides an FOD GUI for the data analysis. This can be found in the tools and software tab of the receiver product you'll be calibrating. This GUI covers all of TI's receivers. Once you download the tool, you find the GUI in the start menu.
Included with the GUI is a detailed user manual that will give you more information on FOD and help walk through the process. The user manual details what equipment will be needed and why. It will cover many details that we don't have time for here. In addition, the TI GUI and the AVID TUI we need, a source meter for the receiver load, an oscilloscope for measuring the voltage on the rec pin, a resistor decade box for our FOD capable of 1K ohms, and a resistor decade box for ROS capable of 500 kiloohms, a volt meter, hyperterminal or tera terminal, to show the results from the AVID tool. And most importantly, you'll need your end equipment.
Our next video will cover the lab data collection and the use of the GUI. Watch for more videos as we take a deeper dive into wireless power at ti.com/wirelesspower. Thanks for watching. [音乐播放] 我希望您曾有机会在 ti.com/wirelesspower 访问 我们的无线 电源概述。 概述涵盖 刚开始接触 无线电源的人 以及希望扩展 知识的人 感兴趣的多个主题。 大家好，我叫 Dick Stacey， 是 TI 电池管理 解决方案团队的 应用工程师。 在本次课程中， 我将讨论用于 外来物体检测 或 FOD 的工具。 接收器和 发送器必须 解决该问题， 但我们将重点 讨论接收器 FOD。 在本次讨论中， 外来物体是 干扰发送器 创建的磁场的 任何物体，它不是 解决方案的一部分。 当放置在电力 传输区域内时， 它们可能会吸收 传输的能量并发热， 这可能会导致 很差的用户体验。 将接收器放置在 发送器上时，发送器 将开始向 接收器发送 电力，它相应地 将协商其系统 需要的电力。 在没有外来物体的 正常操作期间， 传输的电力等于 接收的电力。 在将外来物体 插入系统中时， 它将吸收 从发送器 发送的一部分能量。 然后接收器将 需要从发送器 请求更多的电力， 以补偿外来物体 功率损耗。 通过将向发送器 报告的接收功率 与实际 传输的 功率进行比较， 无线系统能够 确定是否存在 外来物体。 如果该差值 变得过大， 则说明该于区中 存在吸收过量的 传输电力的物体。 一旦达到允许的 最大功率损耗的 预设阈值， 发送器需要 阻止该物体 超过给定的 温度阈值。 通常，发送器将 停止电力传输 并设置错误标识。 许多 TI 发送器 会降低发送功率， 以尝试 保持在 可接受的 水平之内， 从而在不产生过多的 功率损耗的情况下 继续进行电力输送。 接收器系统 需要进行校准， 以确保它向发送器 发送正确的功率水平。 需要进行 校准，以应对 任何预期的 友好金属损耗。 友好金属示例 包括摄像头、 扬声器、电池、 螺钉和连接器。 接收器线圈 屏蔽不仅 用于将磁场 定向到线圈， 而且尽可能 多地阻止 磁场影响 友好金属。 接下来的问题是， 我是否必须单独 校准每个系统？ 我如何针对友好 金属校准我的系统？ 好消息是，校准 某个系统之后， 任何复制的系统 都可以使用该同一 校准，只要它们使用 完全相同的机械 和电气设计即可。 现在，我们将讨论 可用于执行校准的 工具。 系统校准需要 使用外部工具， 我们通常使用 AVID Technologies 的 Qi FOD 发送器来校准 我们的接收器 EVM。 AVID 工具需要 19 伏的电源 和 USB 串行 接口，它们都 包含在该系统中。 TI 提供 FOD GUI， 用于进行数据分析。 可以在您要进行 校准的接收器 产品的工具和软件 选项卡中找到它。 该 GUI 涵盖 所有的 TI 接收器。 您下载该工具之后，可以 在开始菜单中找到该 GUI。 随 GUI 一起包含 一个详细的用户 手册，它将为您 提供有关 FOD 的 更详细的信息， 帮助您完成该过程。 该用户手册详细 介绍了需要什么 设备以及原因。 它将涵盖许多我们 在这里没时间讨论的细节。 此外，对于 TI GUI 和 AVID TUI， 我们需要一个源表 用于测量接收器负载， 一个示波器用于测量 rect 引脚上的电压， 一个十进制电阻箱用于我们的 FOD，能够实现 1K 欧姆， 一个十进制电阻箱用于 ROS， 能够实现 500 千欧姆， 一个电压表， 超级终端或 tera 终端，以显示 AVID 工具的结果。 最重要的是， 您需要您的终端设备。 我们的下一个视频将 涵盖实验室数据收集 和 GUI 的使用。 要更深入地了解无线电源， 请访问 ti.com/wirelesspower 观看更多视频。 谢谢观看。

Description

September 2, 2016

In this session of Wireless Power 101 we discuss the tools used for Foreign Object Detection, or FOD. Both the receiver and transmitter have to address this issue, but this will focus on the receiver FOD. Part of a series of Wireless Power 101 videos that will walk you through concepts and resources from TI.com.